Automatic booster piston for internal combustion engines



Nov. 24, 1959 R. J. COLTON' 2,914,047

AUTOMATIC BOOSTER PISTON FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 1 Filed April 4, 1956 INVENTOR.

Nov. 24, 1959 J. CO LTON 2,914,047

" AUTOMATIC BOOSTERPISTQN FOR INTERNAL COMBUSTION ENGINES Filed April 4, 1956 5 Sheets-Sheet 2 IN V EN TOR.

Nov. 24, 1959 R. J. COLTON 2,914,047

AUTOMATIC BOOSTER PISTON FOR INTERNAL COMBUSTION ENGINES Filed.April 4, 1956 3 Sheets-Sheet 3 IN V EN TOR.

United States Patent AUTOMATIC BOOSTER PISTON FOR INTERNAL COMBUSTION ENGINES Roland J. Colton, Port Washington, NY.

ApplicationApril 4, 1956, Serial No. 576,048

1 Claim. (Cl. 123-48) of available engine power without the use of a supercharger, although a conventional supercharger may be used in conjunction with this device.

Some of the additional advantages include a simple means for changing the compression ratio of the engine by either increasing or decreasing the said compression ratio while the said engine is operating or at rest. Means for more complete expulsion of the products of combustion during the exhaust stroke of the engine cycle, thus causing a reduction in the percentage of inert gas which would otherwise be present within the combustible gas mixture at the termination of the following intake stroke of the engine cycle.

The specification and drawings will enable those versed in the arts to which my invention pertains to construct and use this device.

Referring to the said drawings:

Fig. 1 is a sectional view through one cylinder of a four stroke cycle internal combustion engine wherein a booster cylinder and booster piston are incorporated in the cylinder;

Fig. 2 shows a cylinder head with booster cylinder and control means for variation of the compression ratio of an internal combustion engine of the four stroke cycle type;

Fig. 3 shows a sectional view of a cylinder head wherein a coil spring imparts pressure to a booster piston -within a booster cylinder which is incorporated within the said cylinder head of an engine of the four stroke cycle type; and

Fig. 4 is a sectional view through a booster cylinder showing a booster cylinder wherein means are provided for cooling the contents of the said booster cylinder. This is the preferred type for two stroke cycle engines.

Referring to Fig. 1, this shows the booster cylinder 12 and the booster piston 11, partially in section, together with the primary elements of the engine with which the said booster piston cooperates by its movements in improving the operation of the said engine.

' The conventional cylinder of the engine is shown at 1, with the head of the conventional cylinder shown at 2 with coolant indicated at 3 while a spark plug is shown at 9.

The conventional piston is shown at 4 with the wrist pin at 5, while the connecting rod and crank are shown at 6 and 7 respectively with the crank-pin indicated at 8 and the aforesaid elements in the position usually referred to as top dead center where the wrist pin 5,

Patented Nov. 24, 1959 ice the connecting rod 6 and the crank 7 are all in a straight line while the conventional piston is near the head of the conventional cylinder 2 and the combustion chamber indicated at 18.

An overhead valve is shown while covering a valve port at 10. This valve may be either an exhaust valve or an intake valve, and is fully shown merely for the sake of clarity in the drawing.

The booster piston is shown at 11 and within the booster cylinder 12 which in the example shown, is a pneumatic cylinder, closed at the top by the booster cylinder head 15 which is attached to the booster cylinder by suitable cap screws and furnished with a gasket.

An air or gas conduit is shown at 13 through which compressed air or compressed gas is conducted from the source of air or gas pressure through the conduit 13 and into the booster cylinder, entering the booster cylinder 12 at the terminus of the conduit 13 which is indicated at 17.

To prevent the return of air or gas from within the booster cylinder through the conduit 13, a non-return valve is provided at 14 which valve will close and remain closed so long as air or gas is not passing from within the conduit 13 to the inside of the booster cylinder. The plug 60 permits access to the valve 14. This valve may be any one of the well known types of non-return valves such as a ball check valve as shown, swing check valve etc. and should be placed within the conduit 13 between the booster cylinder 12 and the source of compressed air or gas and as near the booster cylinder as is practical.

The booster cylinder extends from the booster cylinder head 15 to the combustion chamber 18, and is counterbored from the said booster cylinder head to the bevelled shoulder indicated at 19, comprising a cylinder of two different diameters while the booster piston is fitted to the largerv diameter of the booster cylinder by any of the well known means of closely fitting a piston to a cylinder such as metal, carbon or graphite piston rings to prevent the escape of compressed air or while cooperating with a corresponding bevelled shoul der of the booster piston in forming an airtight joint to retard the leakage of compressed air or gas from the booster cylinder into the conventional cylinder during the times when the internal pressure of the conventional cylinder is below the internal pressure of the booster cylinder.

The bevelled shoulder 19 must be of such small dimensions that there will not be an excessive differential in the two diameters of the booster cylinder which would create two objectionable conditions, i.e., carbon would not readily be pulverized and blown free from the bevelled surfaces of the booster cylinder and the booster piston, while the amount of pneumatic pressure acting to raise the booster piston away from the bevelled surface 19 would necessarily be extremely high compared to the initial pressure of the air or gas contained within the booster cylinder. Obviously when the booster piston is forced away from the bevelled surface, then the booster piston area exposed to the pneumatic pressure within the conventional cylinder and the area of the booster piston exposed to the initial air or gas pressure within the booster cylinder would be equal to the said area exposed to the pneumatic pressure within the said conventional cylinder, and disregarding friction of the booster piston and the weight of the said booster piston, then the aforesaid sure balance where the pressures would be equal above and below the aforesaid booster piston.

The operation of this device will be understood by referring to Fig. 1 and assuming that the engine is in operation and the conventional piston 4 is at the completion of the exhaust stroke and about to begin the intake stroke with the conventional valves, i.e. (intake and exhaust valves) functioning in the conventional manner and with the booster cylinder filled with compressed air or gas which compressed air or gas holds the booster piston 11 in the position shown as the conventional piston begins the downward stroke which is the aspirating or intake stroke of the engine cycle.

As the conventional piston completes the intake stroke and begins the next stroke and the conventional valves are closed, the compression of the combustible mixture begins while the pneumatic pressure rises within the conventional cylinder until it is higher than the initial pneumatic pressure within the booster cylinder, thus causing the booster piston to be moved in the direction of the booster cylinder head 15 and further compressing the compressed air or gas contained within the aforesaid booster cylinder until the aforesaid booster piston assumes an approximate position of pneumatic pressure balance while also providing additional space within the combustion chamber 18 and thus limiting the compression ratio within the conventional cylinder.

The amount of additional space which may be added to the combustion chamber during the compression stroke of the conventional piston is dependent upon the bore and stroke of the booster cylinder together with the initial air or gas pressure within the said booster cylinder along with the speed at which the engine is operating, thus any increase in the amount of initial air or gas pressure within the conduit 13 will automatically increase the compression ratio within the conventional cylinder.

When the combustible mixture within the conventional cylinder is ignited and there is the usual additional increase in the pressure within the conventional cylinder, the booster piston once more assumes a new position further into the booster cylinder, thus compressing the air or gas trapped within the said booster cylinder until the said air or gas is subjected to a pneumatic pressure approximately equal to the pressure within the conventional cylinder and the aforesaid booster piston may be said to have assumed a second position of pneumatic pressure balance, except where the aforesaid booster piston contacts the booster cylinder head 15 with the said booster cylinder head 15 becoming a stop limit.

As the conventional piston begins the power stroke and is moving towards the crankshaft, the pressure within the conventional cylinder decreases rapidly, and as the said pressure decreases within the said conventional cylinder, the compressed air or gas within the booster cylinder re-expands and forces the booster piston to automatically cooperate with the said conventional piston in maintaining a position of pneumatic pressure balance until the pressure within the aforesaid conventional cylinder falls below the initial air or gas pressure within the booster cylinder after which the booster piston once again assumes the position shown in Fig. l.

The automatic cooperation between the conventional piston and the booster piston during the working stroke causes an advantageous effect in delaying the pressure drop within the conventional cylinder, thus making available to the conventional piston a greater pressure within the conventional cylinder When the conventional piston is near the half stroke where the connecting rod transsuits the greatest amount of torque to the engine crank- -booster piston would assume a position of pneumatic presshaft for any given pressure within the conventional cylinder.

During the following stroke which is the exhaust stroke of the engine cycle, the volume of the contents of the conventional cylinder is less than it would be within a conventional cylinder having the same bore, stroke and compression ratio and also lacking a booster piston, therefore at the termination of the exhaust stroke of a booster piston equipped engine the volume of the contents of the conventional cylinder is comparable to an engine of extremely high compression ratio and obviously there is a more thorough expulsion of inert gas as the products of combustion which products of combustion are prone to expand during the first part of the following stroke which is the intake stroke.

With all piston type internal combustion engines, no combustible mixture is induced to enter the conventional cylinder until the absolute pressure within the conventional cylinder is below the absolute pressure within the intake conduit, therefore more complete expulsion of the inert gas leaves less inert gas for the inevitable re-expansion and the percentage of inert gas within the combustible mixture of the following charge of said combustible mixture is greatly reduced.

As internal combustion engines are varied as to size, speed, compression ratio, type of fuel used and uses to which they are put, etc., it is obvious that there is no hard and fast rule for the control of the booster piston wherein one method of control is best for all of the aforesaid variations other than the basic cooperationof the said booster piston movements in cooperation with the conventional piston of a four stroke cycle engine wherein the aforesaid booster piston moves farther into the booster cylinder during the compression stroke of the conventional piston after which the aforesaid booster piston moves with resilient force towards the combustion chamber during the working stroke of the aforesaid conventional piston followed by a period of rest for the aforesaid booster piston during the succeeding exhaust stroke and intake stroke of the conventional piston, thus the booster piston executes two strokes to every four strokes of the conventional piston of a four stroke cycle engine.

In the operation of some gasoline driven engines there may be a variety of fuels used at different times, and where low octane fuel is used, obviously it is not advisable to maintain a high compression ratio in the conventional cylinder as when high octane fuel is used, therefore I have provided a simple method of controlling and varying the compression ratio within the conventional cylinder by changing the character of the resilient force acting to hold the booster piston in the position shown in Fig. 1, while the aforesaid booster piston continues to execute the same number of movements in the same sequence as previously described with the booster piston reacting against the gaseous contents of the conventional cylinder with preselected amounts of force and movements which are best suited to the type of fuel being used.

This control means is a simple method of allowing the booster piston to move farther into the booster cylinder to provide additional space within the combustion chamber when it is desirable to reduce the compression ratio, while limiting the travel of the booster piston by increased initial air or gas pressure within the booster cylinder will automatically increase the compression ratio within the conventional cylinder.

The possible scope of this device in varying the compression ratio is readily seen when one considers the fact that an engine having an eight to one compression ratio becomes a four to one compression ratio engine when the available space is doubled within the combustion chamber at the termination of the compression stroke of the conventional piston. Inversely, diminishing the size of the combustion chamber by one half,

creates an eight" to one compressioniatio from four to one. A i

This variation in compression ratio is especially advantageous at high enginespeeds when the conventional piston (without the cooperation of a booster piston) is prone to outrun the incoming inspirated combustible mixture, and the resultant peak of compression at the time of ignition is lower than the optimum pressure due to the fact that the conventional cylinder constitutes an extremely low pressure area during each high speed aspirating or intake stroke, and consequently has a .very small amount of thesaid combustibIe mixture to be compressed at the beginning of the compression stroke, whereas the cooperation of .the saidbooster piston reduces the amount of space wherein the aforesaid combustible mixture is to be compressed with the result being an increase in the ultimate pressure at the time of ignition.

In Fig. 2 I have shown a sectional view through one side of an L head internal combustion engine wherein means are provided for automatic variation, or optional variation in the compression ratio within the conventional cylinder of the said L head engine through the,.variable cooperative movements of the booster piston which. is shown at 11 and confined within the booster cylinder 12 while being capable of limited reciprocating movement within the said booster cylinder.

A part of the conventional cylinder is shown at 1 while the conventional piston is partially shown at 4 with the combustion chamber partially shown at 18, while a bevelled shoulder is indicated at 19 wherein the internal diameter of the booster cylinder is constricted to form a shoulder forthe purpose of providing a positive stop for limiting the downward movement of the booster pis-' ton which is externally machined to the internal contours of the said booster cylinder.

The booster piston is shown in the position it assumes during ignition of the combustible mixture. within the combustion chamber 18 while maintaining low compression ratio. v

The construction of the booster cylinder head .15 and the elements attached thereto provides means for reducing the compression ratio of the engine by opening a non-return valve within the compressed air or.gas conduit 13, so that some .oi the compressed air or gas may escape from within the booster cylinder. 12 tovthe part of the air or gas conduit 13 which extends beyond: the booster cylinder head 15 and in the direction. of the source of air or gas pressure, The said non-return valve i s shown at 23 and is firmly attachedto the non-return valve stem 51 which extends from within a guide sleeve 50 through the element 52 to the element 30which is a push rod comprising a polished metal shaft having a boss formed as indicated at 56 which acts as a stop when contacting the element indicated at 27 which element acts as a closure for the booster piston head and guide for the element 30, while the element 21' is also a..closure as well as a valve stem guide.

A compression spring is shown at 26 which springacts to move the element 30 in a direction away from the contact point indicated at25, ,while a light weight-compression spring indicated at 22 acts to movethenonreturn valve towards the element 57 which is the nonreturn valve seat which seat forms the annular shaped opening around the non-return valve stem 51 as indicated at24.

While the non-return valve 23is held in the open position as shown, then the conduit 13 remains in conimuni cation with the inside of the booster cylinder 12provid ing a free path for compressedair or gas to pass through the booster cylinder head in two directions, thus allowing the booster piston to be forced into the booster cylinder to a greater extent due to theability of the said booster piston to expel compressed air or gas'from within the booster cylinder to ajpoint beyond the said non-return valve23, andin moving further into the 6 booster cylinder there is provided additional space in the combustion chamber which spaceis added to the total space comprising the combustion chamber, and thus the compression ratio'of the conventional cylinder becomes reduced to a'lower compression ratio.

Governing factors in the operation of the non-return valve in lowering and raisingthe compression ratio within the conventional cylinder are the amount of the initial air or gas pressure within the conduit 13 and the cubic contents of the compressed air or gas when expelled from within the booster cylinder.

One method of varying the amount of space wherein the said amount of space contains expelled air or gas from the booster cylinder is the use of an auxiliary nonreturn valve as shown at 42 wherein means are provided to allow. air or gas to pass from the conduit 43 .into the auxiliary non-return valve chamber 58 and thence to the conduit l3, while -a reverseflow will close the auxiliary non-return valve. 42 with the space from the auxiliary non-return valve chamber 58 to the terminus of the conduitat 17, comprising the total space into which air or gas may be compressed after expulsion from the booster cylinder while-the non-return valve 23 is held open by the push'rod element indicated at 30 as indicated in Fig. 2. V

Here it may be seen that closing and opening the non-return valve 23 by pressure of the element. 30 at the point indicated at 25 will cause cooperative elements to lower or raise the compression ratio within the conventional cylinder while there is a substantial air or gas pressure within the conduit 13 .and the internal combustion engine is in operation. I

One means of operating the push rod element 30 may be, for example, by making use of the partial vacuum created within the intake manifold of the. internal combustion engine as shown in Fig. 2 wherein the said intake manifold is shown at 44 with the conduit 39 in communication with the chamber 48 and the said intake manifold 44 through the body of the stopcock 40 and the tapered plug element.41 which may be revolved degrees to close the conduit when desired.

The element 38 and the element 36 are circular pan shaped elements bolted together as shown with a flexible non-metallic diaphragm 34 interposed in aflmanner to form an upper chamber vented to the atmosphereby' the opening shown. at37 while the"lowerjchamber 48 is only in communication .with the intake [manifold 44 via the conduit 39. The cap screw 49 indicates how the vacuum device may be attached to the'engi'ne.

The element 35 iscentrally attached to the diaphragm 34 with the connecting rod 32 pivotallyflattached to the said element 35 by the pin 33'while likewise attachedto the bell-crank 28 bythe pin '31.

The bell-crank 28 is capable of arcuate movement on the shaft 20 which is firmly attached to 'theconventional cylinder head 2 (said attachment not shown) While the projecting finger shown at 29 remains in pressure contact with the element 30 so that rotation of the'element 28 away from the element 30,thus allowing the compression spring 26 to move the element 30 to a point where the boss 56 will contact the element 27, thus providing the amount of movementnecessary to. allow thenonreturn valve spring 22 to move the non-return valve 23 to a position wherethe annular opening 24"will be completely closed by the said non-return valve 23.

In Fig. 2 the motive power for the necessary. rotative movement of the element 28 is transmitted throughthe link element 32 from the diaphragm 34 which in'tum it actuated atmospherically by the partial vacuumwithin the vacuum chamber 48 .whenever the said partial vacuum is highenough to overcome the pressurepfthe compression springs 22 and 26 and allow atmospheric pressure within the element'36 to force thesaid diaphragm to the position shown in Fig. 2.

in a counterclockwise direction will move the finger 29 The aforesaid high vacuum condition within the said chamber 48 may be so utilized that whenever the throttle valve is nearly closediandtheengine speed is decreased with the usual rise in vacuumin the intake manifold 44, the non-return valve -23 is automatically opened, thus providing engine operation wherein the said engine operates as a low compression engine while idling, and as a high compression engine While working, or these operations may be reversed by alterations embodying the simple and well-known meansof reversing link motion. Closing of the conduit 39 by the 90 degree rotation of the plug element 41 while the engine is working will cause the non-return valve 23 to remain in a position whereitonly operates as a non-return valve, and thus the compression ratio of the engine will remain constant.

"In Fig. 2 the shaft .element20 is shown without supporting bearingsin order that otherparts of this device maybe more clearly shown while a description of the necessary bearings required to maintain the shaft element '20' in the position shown is not of prime importance.

Where there isapluralityof cylinders comprising a booster piston equipped engine with cylinders, etc., similar to what is indicated in Fig. 2, then the shaft element 20 would be of such length asto reach allbooster cylinder heads while the bell crank element 28 would be keyed to the shaft element.20 with a pluralitycf finger elements similar to the element 29 and keyed to the element 20 at the positions where all the finger elements would contact their respective push rod elements similar to the element 30 while the motive power for therotative movement of the shaft element 20.may remain as shown in Fig. 2 or motive power may be from other convenient sources.

In Fig. l and Fig. 2 areshown booster pistons wherein the resilient force acting to force the said booster pistons towards the inside of the conventional cylinder is a quantity of gas or air subjected to pneumatic pressure, while in Fig. 3 is shown a sectional view through the upper part of one cylinder and cylinder head of an overhead valve engine with some fragments of parts and embodying a coiled compression spring within the booster cylinder to furnish resilient force to push the booster piston in the desired direction. Where similar parts are shown'in Fig. 1 and Fig. 2 then the indicating numerals are identical.

In Fig. 3 the booster cylinder and booster piston function in the same manner as the elements shown in Fig. l while'the booster cylinder-head embodies a pedestal bearing shown at 53 whichforms a bearing for the valve rocker arm shaft 54 upon which the valve rocker arm 55 is pivotally mounted.

The booster'piston spring is shown in section at 45 while partially contained within a cup shaped recess within the said booster piston. There is no means of cooling this spring'other than through the points of contact with the booster cylinder'head and consequently the metal used in the construction of this spring must have heat resisting qualities to withstand the high temperatures in which it must operate.

In Fig. 4 I have-provideda simple means of cooling the contents of a'spring loaded booster cylinder bythe introduction of a coolant, preferably oil, to be circulated through the booster cylinder through a small coolant inlet conduit as indicated at 46 while the large conduit indicated at 47 allows the reciprocating booster piston to'expel excess coolant andvprcvent the booster cylinder from becoming. filled with coolant to a point where the said coolant may hamper the movement of the said booster piston.

The source of fluid pressure which forces the coolant throughthe booster cylinder maybe from any type of fluidipump or frfomflthe lubricating oil pump or where adiesel engineisinvolved, apart of .the fuel .oil may belutilized as a coolant forthe contentsofthe o s cylinder.

The coolant outlet conduit 47 is shown as a short length of curved tubing, but this tube 47 may be extended to communicate with a mufiier to silence the inevitable noise which is bound to be emitted from such a device when ventedto the atmosphere as is shown.

The substance of the preceding matter describes the construction and action of my invention when applied to a four stroke cycle engine wherein the booster piston movements are one half the number of movements executed by the conventional piston during a given period of time, whereas the movements of a booster piston are equal to the number of movements of the conventional piston when cooperating with the said conventional piston of a two stroke cycle engine.

While the basic construction of the booster piston and booster cylinder should be identical for use in conjunction with a two stroke cycle or four stroke cycle engine, the preferred location of the booster cylinder should be with the said booster cylinder in a vertical position when the conventional cylinder is operated in a horizontal position with the said booster cylinder in communication with the combustion chamber at approximate right angle to the long axis of the convention cylinder. This position allows carbon to fall into the combustion chamber and be carried out of the conventional cylinder via the exhaust conduit.

Where the conventional cylinder and cylinder head are cast in one piece as is the case with most valveless type two stroke cycle engines, then the booster cylinder head would be one extra piece of metal furnished with bolts and gasket to permit easy removal of the booster piston.

All materials used in the construction of this device may be of any type which is found suitable for the service required and all openings from which push rods extend from within air or gas conduits shall be made airtight by suitable packing preferably of the metallic bellows type. I

The method of lubricating the booster cylinders may be similar to any of the methods of lubricating the cylinders of an air compressor such as introducing lubricant entrained in the air or direct injection of the lubricant into the cylinder by force feed metering lubricator.

Non-friction materials such as carbon or graphite may be used as a bushing within the booster cylinder or as a facing on the booster piston to obviate the necessity of lubrication of the said booster cylinder.

The amount of compressed air or gas required for the operation of this device is merely enough to compensate for leakage past the booster piston after the initial air or gas pressure has been built up to the pressure desired. Where the engine is started without air or gas pressure within the booster cylinders, then the engine starts as a low compression engine and the starting motor has less workto do in starting the engine.

The source of compressed air or gas may be from any of the well-known sources such for example as a small compressor (not shown) attached to and driven by the engine.

Although I have hereinshown and described by way of example'one embodiment of the invention and some modifications thereof, it will be understood that I am not to be limited to the exact details shown and described, as many changes may be made in said arrangements within the scope of the following claim.

Having described the invention, I claim:

In an internal combustion engine having a main cylinder with a main piston reciprocally carried therein, a cylinder head for said main cylinder, a booster cylinder formed integrally with said cylinder head, a pneumatically loaded booster piston in saidbooster cylinder, a conduit communicating with said booster cylinder and connected toa fluid medium under pressure, check valve means in said conduit comprising a valve disc carried on a guided valve stem, spring means urging said stem inla directionto seat said valve disc, diaphragm means for unseating said valve disc, means defining a confined space about said diaphragm means, and a connection between said confined space and an intake manifold of said engine for supplying vacuum means to unseat said disk, said vacuum only unseating the valve during idling. 5

References Cited in the file of this patent UNITED STATES PATENTS 752,936 Vogt Feb. 23, 1904 922,613 McClintock May 25, 1909 1,415,025 Folsom May 9, 1922 Italy Apr. 18, 1927 

